Empowering Energy Storage: Advancements in High-Performance Redox-Active Supercapacitors Using Magnesium Ion Technology
Professor Yun Young-su’s group at the KU-KIST Graduate School of Converging Science and Technology developed a magnesium ion-based high-performance redox-active supercapacitor that exhibits a 5-fold higher capacitance than that of the conventional electrode based on an inverse-charging process technology.
Supercapacitors are energy storage devices that store energy through physical adsorption and desorption of ions at the interface between an electrode and an electrolyte. They have advantages, such as fast charge and discharge rates and excellent lifetime characteristics. However, since they have significantly lower energy densities than lithium ion batteries, their application to fast-growing industries, including mobile electronic devices and vehicles, is limited.
The research group became the first in the world to show that the redox-active function can be induced on a nanostructured electrode active material included in a secondary battery cell through a simple inverse-charging technology. With this approach, the research group developed a high-performance redox-active magnesium supercapacitor. The inverse charging technology was controlled by cyclic voltammetry that applies voltage in an inverse direction, and a carbon electrode with an electrochemically-controlled redox-activity was successfully manufactured. In addition, the research group investigated the redox mechanism between the carbonyl functional group generated by inverse charging and the magnesium ions through first-principle calculation.
Finally, using the manufactured redox-active electrode materials as an anode, the research group achieved a 5-fold higher capacitance than the initial capacitance for a wide voltage of 4 V as well as stable charge/discharge over 5,000 cycles. This means that the energy density may be increased to about 2.6 times higher than those of previously reported alkali-ion supercapacitors, indicating that the newly developed supercapacitor has high potential as a next-generation energy storage device.
The research was conducted by Lee Eun-ji, a student in the integrated master-doctoral degree program at KU-KIST Graduate School of Converging Science and Technology under the direction of Professor Yun Young-su, and supported by Professor Lim Hyung-kyu’s group of Kangwon National University and Professor Jin Hyoung-joon’s group of Inha University. The article entitled, “4 V-class magnesium-ion pseudocapacitors fabricated using an in situ inverse-charging process,” became available online in Chemical Engineering Journal on July 29, and will be ultimately published on October 1.